Datasheet

MAX5490
100k Ω Precision-Matched Resistor-Divider in
SOT23
4 _______________________________________________________________________________________
Detailed Description
As shown in the Block Diagram, the MAX5490 consists
of two precision, low-ratio-drift resistors with an end-to-
end resistance of 100kΩ (R
1
+ R
2
). P3 is the set point
of the divider. The maximum working voltage of the
MAX5490 is 80V. This device offers a wide range of
resistance ratios (R
1
/R
2
) from 1:1 to 100:1 and is ideal
for precision operational amplifier gain/attenuation con-
trol. A maximum initial ratio accuracy of 0.035% and a
low 1ppm/°C ratio drift enhance system accuracy.
Applications Information
Self-Heating and Error
Applying a voltage across terminals P1 and P2 causes
the device to heat up due to power dissipation. In high-
voltage applications, consider the error in resistance-
ratio temperature coefficient caused by self-heating.
The worst-case self-heating occurs when the operating
voltage attains its maximum value. Approximate the
result of power dissipation under this condition as:
The thermal resistance from junction to ambient, θ
J-A
,
for a 3-pin SOT23 package is 141°C/W. Calculate the
resulting temperature rise as:
∆T = 64mW x 141°C/W = 9.02°C
If the ratio temperature coefficient is 1ppm/°C (typ), the
total error introduced by self-heating is:
9.02°C x 1ppm/°C = 9.02ppm
P
V
R
V
k
mW
DISS
MAX
=
()
=
()
=
22
80
100
64
Ω
Pin Description
PIN NAME FUNCTION
1P1R
1
Connection Terminal
2P2R
2
Connection Terminal
3 P3 Set-Point Connection Terminal
1000
10
1 100 1k
100
FREQUENCY (Hz)
NOISE (nV/√Hz)
10
SPECTRAL NOISE DENSITY
MAX5490 toc06
RATIO 1:1
SIGNAL CONNECTED TO P2
P1 GROUNDED
V
P1-P2
= 10V
V
P1-P2
= 2V
100
10
1
0.1
0.01
0.001
0.0001
10 1k 10k100 100k
TOTAL HARMONIC DISTORTION
PLUS NOISE RESPONSE
MAX5490 toc07
FREQUENCY (Hz)
THD+N (%)
1:1 RATIO
20Hz TO 20kHz BANDPASS
Typical Operating Characteristics (continued)
(V
P1-P2
= 10V, T
A
= +25°C, unless otherwise noted.)